My invention relates to improvements in an actuator/coupler that couples a towing vehicle to a trailer and that acts to set the hydraulic brakes of the trailer responsive to braking of the towing vehicle.
I have been working on couplers and actuators over a period of years and have conceived of features that would be desirable to have in an actuator/coupler including the following:
1. Concealment of two pairs of rollers in a right-rectangular housing involving telescoping parts consisting of a coupler attached to the ball hitch of the towing vehicle and the housing attached to the tongue of the trailer. Among other advantages, concealment of the rollers would help protect them from the trailer environment (dust, dirt, debris) and from the elements (rain, ice). Also, concealment would improve the appearance of the actuator/coupler. Having a flat, unobstructed surface on the top of the actuator/coupler makes this surface useful as a step in getting into or out of the trailer or a boat supported by the trailer. Essentially the same rear housing can be used to bolt or weld to various trailer tongue arrangements, i.e., either a straight tongue or an A-frame mounting. PA1 2. I have found that concealment of the rollers involves certain problems in practical manufacturing, installation and maintenance, especially in orienting the rollers before their supporting shafts are inserted in the mechanism, so special provisions need to be made for such roller orientation. PA1 3. It is desirable to be able to pull out the coupler from the rear housing as one piece, for improved access in maintenance, repair or replacement. This would facilitate a factory repair or replacement program if desired. The rear housing most likely will be secured to a trailer tongue by bolts or welding. It is desired that the coupler, and the hydraulics, shock absorber, latching mechanism, etc., attached thereto will come free when the front and rear shafts are pulled. These shafts will support front and rear rollers. The only operation needed to pull the coupler, other than pulling the shafts, is detachment of the hydraulic line to the trailer brakes. PA1 4. The reservoir function for the actuator hydraulic cylinder should be adapted for easy inspection of fluid level and for addition of hydraulic fluid as needed, yet the fluid in the reservoir should be protected from the atmosphere with a diaphragm which adapts to various levels of hydraulic fluid. At the same time, the diaphragm construction needs to be economical and commensurate with other actuator/coupler manufacturing costs. The actuator/coupler may be submerged in a lake or other water in launching a boat from a trailer, and hence the diaphragm protects hydraulic fluid when the reservoir is submerged. PA1 5. A practical, reliable, economical system needs to be provided to set and hold the brakes of the trailer in case of accidental trailer uncoupling from the towing vehicle. PA1 6. The usual actuator function involves a telescoping hydraulic piston and cylinder pumping hydraulic fluid to the brakes when the towing vehicle slows and the trailer tends to overrun the towing vehicle. A difficulty with this system arises when the towing vehicle is used to back the trailer and considerable force is required, such as in backing upgrade or over a soft, resistive roadway. An easily operated subsystem needs to be provided to deactivate the normal trailer braking system during backing. This subsystem should be automatically deactivated when the towing vehicle goes forward again, so as to avoid the circumstance that the driver forgets to manually deactivate the subsystem when the backing situation is over. This feature can be provided as an optional addition to an actuator/coupler without the subsystem, so that a purchaser can buy a less expensive actuator/coupler without this feature if he desires.
The objectives of my invention include to provide an actuator/coupler with the features 1,2,3,4,5 and 6 above and to provide an actuator/coupler with other desirable features and characteristics including providing first class quality of construction and including a shape matching common trailer construction from right-rectangular structural members.
My invention will be best understood, together with additional objectives and advantages thereof, from the following description, read with reference to the drawings, in which: